Most applications for use with mobile devices have been designed to be stand-alone applications, with a centralized email server providing e-mail, a telephony system providing voice services, an instant messenger service allowing short, informal chats, etc. However, it has been recognized that these services or tools may be enhanced and may improve efficiency if greater interaction between such services was facilitated.
Consider a situation in which clicking on an e-mail while at home automatically initiated a call from the user's enterprise PBX (Private Branch Exchange) to the e-mail sender, or launched an IM (Instant Messaging) session from a problem tracking system to allow informal communications between a support engineer and the customer. This inter-working has become known as “unified communications”.
One way is to implement a unified communications system within an enterprise. Proprietary protocols may be introduced, “glue” applications may be written to tie together the administration API (Application Programming Interface) published by one company with an equivalent API from another. However, such solutions require substantial effort to introduce inter-operability with services.
One difficulty arises when it is desirous to communicate to a device external to the enterprise. The external device may not receive the same benefits of security and control as those devices within or considered to exist as part of the enterprise.